Race to the Sea — 1914 campaign early in the First World War on the Western Front

Following the failure of the German advance into France at the First Battle of the Marne (5–12 September 1914) and the subsequent First Battle of the Aisne, neither side could break through the other's line. Both the Franco-British and German armies sought to outflank the opponent's northern open flank, each attempting to envelop the other through a series of successive lateral movements northward.

With both sides reaching the North Sea coast, the Western Front solidified into a continuous trench line. Costly and inconclusive battles at the Yser and First Ypres followed. Germany's chief of staff Falkenhayn abandoned hopes of decisive victory and shifted to a strategy of exhaustion. The French army began developing offensive trench warfare doctrine, including infiltration tactics and systematic use of artillery observation from aircraft, which shaped operations for the rest of the war.